Malicious software (or malware), often generically called a virus, is computer software which deliberately does something harmful to a computer or other digital device. Once downloaded, malware can be passed from one computer to another. Malware is usually downloaded to a computer by hiding inside rogue (and sometimes legitimate) software packages: the Trojan horse (or Trojan).
If an operating system (such as Windows, or Mac OS) gets infected by malware, it could cause the loss of important files; business files, digital music and movies, and pictures could be destroyed by a single infection. The malware may use the infected computer to generate revenue (by displaying advertisements, farming private information, or mining cryptocurrency, for example) or simply cause damage. Malware can also interfere with industrial processes, infrastructure, and other business processes if it has access to related devices.
Infectious Mobile Devices
Android and Apple iOS mobile operating systems are vulnerable to malicious code as well. This can come from PDF files, applications, and a variety of other sources. This malware may affect the infected device, or it could act as an asymptomatic carrier, allowing cybercriminals to access confidential information on in or other devices connected to it, intercept phone conversations or take over other aspects of the infected device.
While Mac malware is scarcer than Windows malware, over the last ten years threats targeting Mac OS X have been on the rise and have become more sophisticated. In addition, Macs can pass on files that contain malware to Windows users. For this reason, a layered approach to security is the best defense, including the use of a firewall and Mac antivirus that detects and stops Windows viruses as well as Mac malware.
Since the iOS is shared across all Mac devices, malware targeting this operating system will sometimes lay dormant until it is connected to another device. For example, one kind of malware will infect an iPhone but remain dormant. Once it is connected to a MacBook (through a wired or wireless connection) it infects that. The malware will also infect any other iOS device available, such as an iPod or iPad. After a time, it can gather information from every device the individual owns, essentially stealing their entire online (and quite possibly real) identity. Such malware is sometimes used by hackers to open a back door into these devices so they can manually lock the entire set of devices and copy everything off of them.
In addition to the Linux Virus, Macro Virus, Windows Virus, and Mac Virus, a number of other types of malware exist for computer operating systems. This includes spyware, adware, and scareware (rogue software that claims to serve a purpose, usually pretending to be security software).
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- Definition: Trojan horse, searchsecurity.techtarget.com, (Accessed July 13, 2011).
- Apple Macintoshes Targeted by Porn-Based Computer Virus, FOXNews.com, November 02, 2007.
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- Amy Gahran. iPhone, iPad users: Watch out for malicious PDF files, CNN, July 11, 2011.
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- 10 Years of Mac Malware: How OS X Threats Have Evolved (Infographic)